In recent years, there has been an explosion in the physical fitness industry, and correspondingly, in the desire for equipment which improves an individual's performance of activities which promote good health. One area which has experienced particular growth involves low-impact cardiovascular exercise, an endeavor known to improve physical condition without unduly taxing an individual's joints. Activities such as walking have thus become popularized, and have developed into competition sports such as race walking. The sport serves as an increasingly popular form of exercise and recreation, attracting persons of diverging levels of skill and physical ability. The fitness industry, however, has been slow in recognizing this trend, and has yet to develop an acceptable walking shoe. Walkers have thus been forced to make do with running shoes, shoes designed to accommodate a high impact activity which requires very different foot posture, impact absorption, and overall shoe use. A need has thus developed for a shoe which is designed particularly for use by walkers.
Focusing for a moment on walking technique, it is to be appreciated that walking consists of a series of steps, each step constituting a cycle wherein the walker shifts from a single support phase ("SSP"), to a double support phase ("DSP"), and then back to the single support phase. In the single support phase, the walker's entire weight is balanced on one foot, the other foot being moved forwardly so as to move the walker into the double support phase. In the double support phase, the walker's weight is balanced between a leading and a trailing foot. The trailing foot is used to push the walker forward so as to again enter the single support phase, and begin the cycle anew. The aforementioned "push-off" begins during the single support phase when the walker's center of gravity (COG) passes over the supporting foot. The walker, at all times, has at least one foot in contact with the ground, reducing the impact associated with each step, and resulting in an overall healthier exercise routine.
With each step, the athlete's forward foot lands on the heel, and moves forward to a planted position with the heel and ball of the foot supported from below. The ball of the foot acts as a fulcrum, the walker's foot pivoting forward about such fulcrum as his or her center of gravity passes thereover. This accommodates push-off by the walker's toes. The walker may not push-off with the trailing foot until the leading foot is planted so as to provide the walker with a stable support. A slight forward lean, on the order of approximately 5-degrees from vertical, provides the walker with an ideal walking posture and helps with forward momentum. Such lean should be from the ankles, rather than from the waist because a forward bend from the waste shortens the walker's stride and compromises breathing power by cramping his or her lungs.
In a conventional shoe, the wearer's heel is elevated relative to the toes and the ball of the foot when the foot is planted. This arrangement leads to improper walking posture, and detracts from the wearer's walking power and walking speed. Because of the forwardly declining orientation of the wearer's foot, the wearer will tend to stand with his or her body reclined slightly so as to maintain balance. This results in an unhealthy posture and increases the likelihood of injury to the walker's lower torso. Conventional shoes also detract from walking efficiency because it is necessary to provide a sole with an undersurface which is generally planar from the shoe's heel to the tip of its toe. Such a planar surface is made necessary in order to provide adequate balance for the wearer in view of the elevated heel. The planar sole makes push-off more difficult, the wearer being required to provide a force which will both provide motive force and bend the forepart of the shoe.
It is therefore a general object of the invention to provide a shoe which is designed to facilitate walking, and more particularly, to increase walking speed.
Another general object of the invention to provide a shoe which enhances the wearer's power and endurance by promoting proper walking posture so as to reduce the risk of injury and improve the efficiency and power of a wearer's steps.
It is a further object of the invention to provide a shoe with a sole which inclines the wearer's foot forwardly relative to the bottom surface of the shoe.
Still another object of the invention is to provide a shoe which employs a sole configured to act as a lever, allowing the wearer's interior tibialis to relax, while the larger calf muscle is used to provide the motive force.
It is further desired to provide a shoe which more readily shifts the athlete's center of gravity forward onto a forward portion of the shoe so as to throw the walker forward, shortening the double support phase, and correspondingly, increasing the walker's speed.